Addition of melatonin to the pharmacotherapy of schizophrenia elevates mood and daytime functioning in addition to improved sleep in schizophrenia patients. Melatonin, apart from being a hypnotic and circadian rhythm restoring compound, also possess neuroprotective, anti-neuroinflammatory and antioxidant properties. The rate limiting step of melatonin biosynthetic pathway is the alkylation of serotonin to N- acetyl serotonin, catalyzed by enzyme AANAT (aryl-alkylamine- N-acetyl-transferase). Study of AANAT enzyme and its modulation to achieve normal rhythmical secretion of melatonin can also be a potential target for resynchronising the circadian rhythm.